Food Allergy - Eczema Link Explored

Irritated, inflamed skin may set the autoimmune response leading to food allergies in motion.

Food allergies are something every parent fears. We have all read stories of children experiencing a life-threatening allergic reaction to foods such as nuts or eggs. In fact, preschools and day care centers have become nut-free zones.

So a British study's findings, that a baby's itchy eczema inflammation may initially trigger allergies, could be a game-changer, shifting the focus of food allergy research away from food and the gut and instead toward the skin.

The just-reported study shows that breakdown of the skin barrier in eczema leaves immune cells in skin exposed to environmental allergens.

The researchers cautioned that food sensitivity does not always lead to clinical allergy.

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“The first evidence came from research published in 2003 in the New England Journal of Medicine, showing that infants whose mothers had used peanut protein-containing creams on the baby had a significantly higher risk of peanut allergy than controls,” lead author Carsten Flohr, MD, senior lecturer at King’s College London, told TheDoctorin an e-mail.

Flohr and his colleagues found that babies with broken skin, particularly if they also have eczema, are more than six times as likely as healthy infants to be sensitized to different foods such as eggs, cow's milk, and peanuts.

The British researchers analyzed data from over 600 three-month-old babies enrolled in the EAT (Enquiring About Tolerance) Study. All of the babies were exclusively breastfed from birth. The scientists examined the infants for eczema, tested how much water the skin was able to retain, and screened for gene mutations associated with eczema.

They then carried out skin prick tests to see whether the infants were also sensitized to the six most common allergenic foods. Egg white was the most common allergen, followed by cow's milk, and peanuts. The more severe the eczema, the stronger the likelihood of food sensitivity, independent of genetic factors. However, the researchers cautioned that food sensitivity does not always lead to clinical allergy, and further follow up of the EAT Study children is currently underway.

The babies enrolled in the study were exclusively breastfed, so they had not yet ingested any solid foods. This suggests that active immune cells in the skin, rather than the gut, may be important for food sensitization. It is thought that the breakdown of the skin barrier in eczema leaves active immune cells found in skin exposed to environmental allergens, such as food proteins, which then triggers an allergic response.

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“This work takes what we thought we knew about eczema and food allergy and flips it on its head: we thought that food allergies are triggered from the inside out, but our work shows that in some children it could be from the outside in, via the skin. The skin barrier plays a crucial role in protecting us from allergens in our environment, and we can see here that when that barrier is compromised, especially in eczema, it seems to leave the skin’s immune cells exposed to these allergens,” Flohr said in a university press release.

What Can A Parent Do?

When asked what parents can do to prevent food allergies in their children, Flohr replied, “This is a difficult one.” The EAT Study is testing whether the early introduction of allergenic foods while babies are still being breastfed might help. They also hope to see if reducing the risk of eczema has a preventative effect on the risk of food allergy.

Dr. Flohr added that The Centre of Evidence Based Dermatology in Nottingham, U.K. is currently conducting the Barrier Enhancement Eczema Prevention (BEEP) Study, using moisturizers from birth on children with a family history of eczema to see whether this reduces the incidence of eczema.